1. Field of the Disclosure
The present subject matter relates to a cassette actuation assembly and an associated gasket member for use in combination with a fluid processing system.
2. Description of Related Art
Whole blood is routinely separated into its various components, such as red blood cells, platelets, and plasma. Conventional blood processing methods use durable centrifuge equipment in association with single use, sterile processing sets, typically made of plastic. The configuration of the single use processing sets used in combination with different centrifuges varies widely, but some sets include a molded plastic piece commonly referred to as a cassette. As used herein, the term “cassette” refers to a component of a blood processing system which includes a number of defined fluid passageways and valve stations. The cassette is secured to a cassette holder of the durable equipment. The cassette holder includes actuators for opening and closing the valve stations, which determine which of the fluid passageways are connected to each other, thereby directing fluid between a number of sources and destinations.
An exemplary cassette and cassette holder are employed by the AMICUS® system marketed by Fenwal, Inc. of Lake Zurich, Ill. One version of the AMICUS® system is described in greater detail in U.S. Pat. No. 5,868,696, which is hereby incorporated herein by reference. In the AMICUS® system, fluid flow is controlled by a disposable cassette with preformed fluid passages, which interfaces with an array of actuators and sensors located on a panel of the durable reusable hardware. The cassette has a flexible membrane on the side facing the actuators and sensors. In the prior device, vacuum is applied by the hardware through small spaced-apart apertures to draw the membrane into contact with the surface of the array and with the sensors therein for more reliant and accurate sensing. Specifically, a thin, elastomeric membrane or gasket is associated with the cassette holder of the AMICUS® system and covers all of the actuators. The gasket protects the actuators from liquids, dust, and other debris that could otherwise interfere with the performance of the actuators. However, the gasket described in U.S. Pat. No. 5,868,696 is simplistic (being a plain sheet of elastomeric material and a hydrophobic material therebelow) and the need exists for an improved gasket which adequately shields the relevant portions of the cassette holder while providing additional functionality during blood processing procedures.